This is actually a really cool example of a rare kind of Surmene-made long knife/dagger! From roughly the middle of the 19th century to the first half of the 20th (at least based on what I've seen) different workshops in the Northeastern Anatolian town of Surmene made a variety of different knives, daggers, and short swords. I say "Anatolian" here rather than Turkish, mind you, because to my knowledge Surmene is and has historically been populated mostly by the
Laz people, who by the 19th century had
developed their own sword (or were at least one of the main ethnic groups using them). It seems that then in turn Surmene-based Laz artisans adopted the multi-fullered, curvaceous characteristics of these swords for their own smaller products like knives and daggers. Whilst some of these are of good quality and might have been used locally (which I'd argue includes the specific kind this thread is looking at), many of these products were produced for external/tourist consumption, much like the flamboyant arms and armor produced during the Qajar dynasty in Iran.
Anyways, before your post AHite, I was convinced that there were only 3 surviving examples of this specific kind of Surmene dagger out there! This variety is distinct for its robust blade, tight fullers, qaddara-like blade design, and intricate decoration at the forte. It is also noteworthy that so far 3/4 of the extant examples I've found have distinct Laz-style leatherwork on either their grip, scabbard, or both; something that is unique as not all Surmene items have this distinct cultural marker on them, and I would argue that their inclusion (which is completely optional) is what distinguishes locally used items from those that were made for/consumed by tourists.
Finally just to explain the four images I've attached here: the first two were both sold on eBay at the same time by the same seller, the second example (on the glass table) being the one I acquired, mostly due to the blade being in better condition (though ironically the leather is more worn). The third image/example, also sold on eBay, lacks the Laz leatherwork and scabbard altogether, but actually has superior engraving and even a makers mark stamped at the forte (which I can provide a closer image of if anyone wants to take a crack at deciphering it). The last example - which is clearly of inferior quality and likely from a completely different workshop/set of artisans - I've included simply to show that while this design is not wholly unique when it comes to Surmene-made products, most do not reach the same level of quality, even when they are clearly imitating the same shape/design.